Central Visual Processing I Lec12 Flashcards Preview

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Flashcards in Central Visual Processing I Lec12 Deck (89)
1

The retina ganglion cells have 3 pathways:

magno, parvo, k pathway

2

Visual fields are ___ and ___ in the retina.

flipped and inverted

3

in the optic chiasm, ___ axons cross

nasal axons (temporal visual field)

4

nasal axons carry information from the

temporal visual field

5

in the optic chiasm ___ axons stay ipsilateral

temporal

6

LGN has 6 layers

the 2 magnolayers are ___

ventral

7

LGN has 6 layers

the 4 parvo layers are ___

dorsal

8

in the lgn, the inputs are segregated by

eye

9

lgn gets feedback input from 

V1’s layer 6

10

V1 is ordered ____

retinotopically

11

in v1, more cortical area is given to

central vision/fovea

12

order of M,P,K in V1 

M, P, and K pathways mix substantially here

M pathway is still partially seperated to provide a fast motion processing

13

All V1 neurons have retinotopy which is a ___ field position

receptive

14

V1 neurons are that orientation tuned

interblobs 

look at angle of a light bar --> edges

15

V1 neurons that are center/surround 

blobs

16

The V1 functional unit is a ____

hypercolumn

17

Ocular dominance hypercolumn =___ and ___ columns

 right eye column + left
eye column

18

A complete hypercolumn = 

ocular dominance hypercolumn
+ orientation hypercolumn + color blobs

19

One hypercolumn  contains all the cortical machinery to fully analyze one point in visual space for all ___ and ___

orientations and both eyes

20

Input from optic radiations goes to___ in V1

 layer 4

21

Output of V1 going to V2 leaves from ___

layers 2&3

22

Output from V1 to superior colliculus leaves from

 layer 5

23

Feedback from V1 back to LGN leaves from

 layer 6

24

___ has large (1.5mm) stripes that stain with cytochrome oxidase

V2 

25

Dorsal pathway to ____ visual cortex

parietal

26

Ventral pathway to ___ visual cortex

temporal

27

the where pathway is the

dorsal pathway

28

the what pathway is the 

ventral pathway

29

the where pathway is  involved with

motion and
object localization

30

the what/ventral pathway si involved with

pattern and object recognition. 

31

As you go to higher cortical areas... ___ integrate, summate, and enlarge

Receptive fields 

32

lesions in higher cortical areas (above v1) usually manifest as specific visual deficits like 

loss of color vision or form vision

33

lesions in V1 manifest as__ or ___

 blindness or scotomas

34

ganglion cells in the retinal detect what (4)

 spatial representation (receptive fields & retinotopy)
• retinotopy - the mapping from the retina to initial neurons
- luminence / intensity (esp. rods)
- spectral absorption (cones, color)
- spatial contrast (center/surround, ON/OFF,
edges)

35

spatial contrast is related to

center surround receptive fields

36

output from the retinal ganglion

1. lgn

2. superior colliculus

3. hypothalamus

4. pretectum

 

37

what is another name for the retinogenciulate pathway

the visual processing pathway

38

the superior part of the viosual field lands on the ___ part of the retina

inferior

39

right superior field projects on to the ___ of the retina

bottom left of the retina 

40

 first neurons that get binocular input are in the ___

striate cortex, not the lgn

41

the left visual field gets represented in the ___ hemisphere

right

42

X optic nerve ---> 

complete scotoma

43

X optic chiasm: 

bitemporal hemiopia. 

44

X optic tract on the right

lose  left visual field 

45

lesion of optic radiations

Quadrantanopia

46

leison of occipital cortex typically causes ___ hemianopias 

macular sparing

47

If Meyer's loop (temporal pathway) is lesioned, the Quadrantanopia is ____ superior

48

 if Baum's loop (parietal pathway) is lesioned in the optic radiations, the Quadrantanopia  is ___

inferior

49

lgn cells are binocular or monocular?

monocular.. they have functional segregation

50

the __ pathway is very important for motion

M

51

the __ pathway is involved with visual acuity & color

P

52

the ___ pathway is involved with temporal resolution and luminance contrast

m

53

Common properties of receptive fields in the retina and LGN (3)

center surround organization

mix of cells with on/off center

retinotopically ordered

54

what may be color opponent (red/green or blue/yellow)

retinal ganglion or LGN

55

within the ocular dominance columns are the ___ columns

orientation

56

an on cell you get AP when light is shown in the

center

57

each visual ___ neuron has a receptive field which is part of a retinotopic representation
and has receptive field proepries such as ocular dominance, orientation, and perhaps
other properties

cortical

58

with ___ you dont see red without analyzing green as well

color opponency

59

type II color opponentn cell is depolarized with __ and hyperpolarized with ___.

red and green

60

doube opponent receptive fields encode both __ and ___ contrast

spatial and chromatic 

 

e.g. in center red is on, green off

in surround red is off and green is on

61

type ___ cells have spatial opponency and a weak color bias

type 1

62

___ can be type 1, type 2, or double opponent

blobs

63

are blobs monocular or binocular?

monocular

64

what is "oriented in V2?"

thick disaprity and pale

65

bilateral X of the ___ leads to a behavioral deficit ina  task that requires the discirimination of objects

temporal lobe

66

bilateral X of the ___ leads to a behavioral deficit ina  task that requires the discrimination of locations

parietal

67

The Magno system is specialized for high ___ and ___

temporal resolution (speed) and higher contrast gain,

68

The K pathway is probably also specialized for ___ perception.

color

69

what has center surround reeptor fields?

LGN and the retina

70

Within __, the M, P and K pathways intermix substantially

V1

71

V1 is highly __, with more cortex devoted to central vision.

retinotopic

72

The anatomical structure of V1 is a 2mm thick sheet of cells, with__ layers

 6

73

If you record from a V1 neuron, if may have ___ domiannce or be ___

ocular domiannce or be binocular

74

instad of center surround receptive fields, cells of v1 have ___ receptive fields

oriented

75

Orientation tuning refers to the preference of a cell to be stimulated by an ___ of light presented at a particular angle

edge

76

There are some V1 neurons that are not orientation tuned, but have center- surround receptive fields and are___

 color-opponent

77

The ocular dominance (OD) columns alternate between 

left and right eye

78

Neighboring columns of oriented cells in v1 usually have similar but slightly different ___ tuning

orientation

79

So in general V1 neurons have, simultaneously,

1. a receptive field position (reitnopathy)

2. an ocular domiannce

3. preferred orientation

80

The segregation between the color blob
cells and the regular, oriented V1 cells found in the “interblobs” is the beginnings of the segregation between the “___ and ___

form” vision and color vision pathways,

81

collection of orientation columns that would cover all the possible orientations, from horizontal through vertical and back, for a

 given point in visual space.

82

The orientation column map and the ocular dominance column bands are interwoven in V1 and run

at right angles to eachother

83

There are two major visual processing streams after V2: the___ and ___ pathway

 dorsal pathway and the ventral pathway.

84

 V1: blobs -> ____ stripes in V2

thin

85

V1 interblobs -> ___ (inter) stripes in v2

pale

86

 layer 4B in V1 -> ___ stripes in V2

thick

87

what is retinotopically organized?

v2 and v1

88

The V2 pale stripes contain oriented cells, often end-stopped and probably involved in the detection of 

curvature.

89

The V2 thick stripes contain oriented, disparity cells and are probably involved in

 stereo depth vision.